5.1 Bit and Byte Swapping

DDR3L memories support bit swapping, a technique the designer can use to interchange data lines with one another, provided that they correspond to the same byte lane (e.g. any bits inside the D[0..7] lane). This is very useful when trying to optimize a DDR layout routing.

The following figure shows an example of the bit swapping technique which can be implemented in a SAMA5D2 board design.

Figure 5-1. DDR3L Bit Swapping

Byte swapping is another technique that can be used on DDR3L memories. It allows the designer to swap the data lanes with one another, also for the purpose of optimizing the layout. Remember to also swap the DQMx and DQSx signals corresponding to the swapped byte lanes, as illustrated below.

Figure 5-2. DDR3L Byte Swapping